The present invention relates to a sync generator, video processor. More particularly, the invention relates to a sync generator, video processor of a color video system.
In television apparatus, and especially in apparatus for processing color video signals in the National Television Standards Committee (NTSC), video processor amplifiers are used to provide various processing functions to the video signal. Thus, the video processor amplifiers function to reinsert sync, blanking and burst signals and to provide control of the video signal components such as video level, setup level, sync level, burst level, chroma level and burst phase.
Another parameter which is very important with regard to color phase matching and/or color frame recording is the phase relationship which exists between the leading edge of the horizontal sync pulse and the zero crossover of the sub-carrier to horizontal (SCH) phase. This parameter is critical when the video signal is to be color phase matched to another signal or when the signal is to be recorded for editing at a later time. Problems arise if the SCH of the two signals is not identical, when an attempt is made to color phase match video signals. Horizontal shifts may occur under this condition.
Another problem is the setting of the correct SCH on a composite video signal. There are two possible correct settings for the SCH. This is because the SCH is set without knowing which field is being observed. The setting of the SCH then defines the field sequence. What should be done is to first define the field sequence and then set the SCH. This eliminates the ambiguity in correctly setting the SCH.
Still another problem is the maintaining of the correct SCH in the output video with different SCH input reference signals. Known circuits solve only half the problem, since, although they do maintain the output SCH, they also interchange the field sequence while maintaining it. Thus, for example, 1-2-3-4 becomes 3-4-1-2. This is due to the fact that the horizontal (H) sync is clocked by two times the sub-carrier, resulting in the H sync being clocked in steps of one half cycle of the sub-carrier, or 140 nanoseconds.
The principal object of the invention is to provide a sync generator, video processor which enables the SCH to be correctly set.
An object of the invention is to provide a sync generator, video processor which provides positive identification of the four field color sequence, thereby enabling the correct setting of the SCH.
Another object of the invention is to provide a sync generator, video processor which automatically maintains the setting of the SCH after it has been correctly set, regardless of different input SCH references.
Still another object of the invention is to provide a sync generator, video processor which provides a reference for outside systems by encoding the field identification (ID) on the output video.
Yet another object of the invention is to provide a sync generator, video processor which functions as full sync generator capable of driving any video source.
An object of the invention is to provide a sync generator, video processor which functions as a blanking width verification (BWV) circuit.
Another object of the invention is to provide a sync generator, video processor which functions as a video source identification (VSID) circuit.
Still another object of the invention is to provide a sync generator, video processor which functions as a vertical interval test signal (VITS) inserter.
An object of the invention is to provide a sync generator, video processor which functions as a digital remote control.
Another object of the invention is to provide a sync generator, video processor which functions as a vertical interval reference signal (VIRS) inserter.
Still another object of the invention is to provide a sync generator, video processor which provides multi-function video signal processing, including color field identification, automatic setting of the SCH, and BWV.
Yet another object of the invention is to provide a sync generator, video processor which significantly reduces video tape or match frame editing time and studio setup time.
An object of the invention is to provide a sync generator, video processor which is economical in operation and is a single compact unit for multi-function video processing.